Highly Efficient Electroreduction of CO2 to Ethanol via Asymmetric C-C Coupling by a Metal-Organic Framework with Heterodimetal Dual Sites

Zhen-Hua Zhao; Jia-Run Huang; Pei-Qin Liao; Xiao-Ming Chen

doi:10.1021/jacs.3c08974

Highly Efficient Electroreduction of CO₂ to Ethanol via Asymmetric C-C Coupling by a Metal-Organic Framework with Heterodimetal Dual Sites

J Am Chem Soc. 2023 Dec 13;145(49):26783-26790. doi: 10.1021/jacs.3c08974. Epub 2023 Nov 28.

Authors

Zhen-Hua Zhao¹, Jia-Run Huang¹, Pei-Qin Liao¹, Xiao-Ming Chen^{1

2}

Affiliations

¹ MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, GBRCE for Functional Molecular Engineering, School of Chemistry, IGCME, Sun Yat-Sen University, Guangzhou 510275, China.
² Chemistry and Chemical Engineering Guangdong Laboratory, Shantou 515031, China.

PMID: 38014883
DOI: 10.1021/jacs.3c08974

Abstract

The electroreduction of CO₂ into value-added liquid fuels holds great promise for addressing global environmental and energy challenges. However, achieving highly selective yielding of multi-carbon oxygenates through the electrochemical CO₂ reduction reaction (eCO₂RR) is a formidable task, primarily due to the sluggish asymmetric C-C coupling reaction. In this study, a novel metal-organic framework (CuSn-HAB) with unprecedented heterometallic Sn···Cu dual sites (namely, a pair of SnN₂O₂ and CuN₄ sites bridged by μ-N atoms) was designed to overcome this limitation. CuSn-HAB demonstrated an impressive Faradic efficiency (FE) of 56(2)% for eCO₂RR to alcohols, achieving a current density of 68 mA cm^-2 at a low potential of -0.57 V (vs RHE). Notably, no significant degradation was observed over a continuous 35 h operation at the specified current density. Mechanistic investigations revealed that, in comparison to the copper site, the SnN₂O₂ site exhibits a higher affinity for oxygen atoms. This enhanced affinity plays a pivotal role in facilitating the generation of the key intermediate *OCH₂. Consequently, compared to homometallic Cu···Cu dual sites (generally yielding ethylene product), the heterometallic dual sites were proved to be more thermodynamically favorable for the asymmetric C-C coupling between *CO and *OCH₂, leading to the formation of the key intermediate *CO-*OCH₂, which is favorable for yielding ethanol product.